Meanings
- idiomaticIndicates that something is a secret and not to be divulged.
She doesn't know anything about it yet, so mum's the word, OK?
2 more examples
… and that mum is the word till I give you liberty to speak
1879, Anna Katharine Green, The Leavenworth Case: A Lawyer's Story, G. P. Putnam's Sons, page 256“Well, does she know how you feel?” “Honestly, Charmaine, I do not even know how I feel.” “Aw. Well, you should tell her.” “I should tell no one! Can you keep this secret, Charmaine?” “Mm-hmm.” “Good. Because if you don't, I'll kill you in your sleep.” “Okay, mum's the word.”
2024 November 18, Jeremy Levick & Rajat Suresh, “March Madness” (18:44 from the start), in What We Do in the Shadows, season 6, episode 7, spoken by Charmaine Rinaldi (Marissa Jaret Winokur)
Origin
From mum (“silence”). Recorded since 1704.
Full word history & related roots →Translations
Arabic السر في بئر
- السر في بئرindicates that something is a secret
Catalan muts i a la gàbia
- muts i a la gàbiaindicates that something is a secret
Chinese Mandarin 保密
- 保密 (bǎomì)indicates that something is a secret
Dutch mondje dicht
- mondje dichtindicates that something is a secret
Estonian ära kellelegi räägi
- ära kellelegi räägiindicates that something is a secret
French motus et bouche cousue
- motus et bouche cousueindicates that something is a secret
German Behalte es für dich, pst
- Behalte es für dichindicates that something is a secret
- pstindicates that something is a secret
- pschtindicates that something is a secret
Italian acqua in bocca
- acqua in boccaindicates that something is a secret
Persian شتر دیدی ندیدی
- شتر دیدی ندیدی (šotor didi nadidi)indicates that something is a secret
Polish ani mru-mru
- ani mru-mruindicates that something is a secret
Portuguese bico calado, boca de siri
- bico caladoindicates that something is a secret
- boca de siriindicates that something is a secret
Russian об э́том ни гугу́, об э́том молчо́к
- об э́том ни гугу́ (ob étom ni gugú)indicates that something is a secret
- об э́том молчо́к (ob étom molčók)indicates that something is a secret
Spanish chitón
- chitónindicates that something is a secret
Welsh taw piau hi
- taw piau hiindicates that something is a secret
Cite this entry
mum's the word. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/mum's%20the%20word
“mum's the word.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/mum's%20the%20word. Accessed November 5, 2026.
WatkinsX Dictionary, s.v. “mum's the word,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/mum's%20the%20word.
Source: mum's the word on Wiktionary, CC BY-SA 4.0.